Resolving the Structure of a Well-Ordered Hydroxyl Overlayer on In 2 O 3 (111): Nanomanipulation and Theory

作者：M. Wagner, Peter Lackner, Steffen Seiler, Achim Brunsch, Roland Bliem, Stefan Gerhold, Zhiming Wang, Jacek Osiecki, Karina Schulte, L. A. Boatner, Michael Schmid, Bernd Meyer, Ulrike Diebold · 发表于：ACS Nano · 年份：2017 · DOI：10.1021/acsnano.7b06387 · 被引用次数：58 · 研究领域：Electronic and Structural Properties of Oxides、ZnO doping and properties、Surface and Thin Film Phenomena

High Resolution Image Download MS PowerPoint Slide Changes in chemical and physical properties resulting from water adsorption play an important role in the characterization and performance of device-relevant materials. Studies of model oxides with well-characterized surfaces can provide detailed information that is vital for a general understanding of water–oxide interactions. In this work, we study single crystals of indium oxide, the prototypical transparent contact material that is heavily used in a wide range of applications and most prominently in optoelectronic technologies. Water adsorbs dissociatively already at temperatures as low as 100 K, as confirmed by scanning tunneling microscopy (STM), photoelectron spectroscopy, and density functional theory. This dissociation takes place on lattice sites of the defect-free surface. While the In 2 O 3 (111)-(1 × 1) surface offers four types of surface oxygen atoms (12 atoms per unit cell in total), water dissociation happens exclusively at one of them together with a neighboring pair of 5-fold coordinated In atoms. These O–In groups are symmetrically arranged around the 6-fold coordinated In atoms at the surface. At room temperature, the In 2 O 3 (111) surface thus saturates at three dissociated water molecules per unit cell, leading to a well-ordered hydroxylated surface with (1 × 1) symmetry, where the three water O W H groups plus the surface O S H groups are imaged together as one bright triangle in STM. Manipulations wi...